As defense secretary, Ashton Carter would face a daunting pile of problems at home and abroad. And then there are the unforeseen crises, the ones that explode onto a Pentagon chief's agenda without warning.

By Robert Burns, Lolita C. Baldor, Associated Press

Viewers submitted many questions about our report on the largest psychological program in the Army's history. Col. Marsha Lilly of the Comprehensive Soldier Fitness Public Affairs Office and critic Bryant Welch, a psychotherapist, answer some below.